Random Shortest Path Example: Multiple Instances 10/04/01 13:16:13 PAGE 1 GAMS Rev 121 Linux/Intel 2 4 option limrow=0, limcol=0, solprint=off; 5 6 set iter/iter1*iter100/; 7 8 scalar 9 density/.01/ 10 successful/0/ 11 averageLength/0/ 12 proportionOfSuccess; 13 14 set 15 nodes /1*1000/; 16 17 alias (nodes,i,j,k); 18 19 set arcs(i,j); 20 parameter distance(i,j), supply(nodes); 21 22 variables f(i,j), shortestPathLength; 23 positive variable f; 24 25 * fix source and destination nodes 26 supply('1') = 1; 27 supply('1000') = -1; 28 29 equations balance(i), objective; 30 31 balance(i).. 32 sum(arcs(i,k), f(arcs)) - sum(arcs(j,i), f(arcs)) =e= supply(i); 33 objective.. 34 shortestPathLength =e= sum(arcs, distance(arcs)*f(arcs)); 35 36 model short/balance, objective/; 37 38 option seed=25671; 39 loop(iter, 40 arcs(i,j) = yes$(uniform(0,1) < density); 41 arcs(i,i) = no; 42 distance(arcs) = uniform(1,10); 43 solve short using lp minimizing shortestPathLength; 44 if(short.modelstat < 2, 45 successful = successful+1; 46 averageLength = averageLength + shortestPathLength.l; 47 ); 48 ); 49 50 averageLength = (averageLength / successful)$(successful > 0); 51 proportionOfSuccess = successful / card(iter); 52 53 option averageLength:8; 54 display "Arc Density ", density; 55 display "Proportion of Successful Paths: ", proportionOfSuccess; 56 display "Average length of Successful Paths: ", averageLength; 57 Random Shortest Path Example: Multiple Instances 10/04/01 13:16:13 PAGE 2 Model Statistics SOLVE short USING LP FROM LINE 43 GAMS Rev 121 Linux/Intel LOOPS iter iter1 MODEL STATISTICS BLOCKS OF EQUATIONS 2 SINGLE EQUATIONS 1001 BLOCKS OF VARIABLES 2 SINGLE VARIABLES 10166 NON ZERO ELEMENTS 30496 GENERATION TIME = 0.390 SECONDS 2.9 Mb LNX200-121 EXECUTION TIME = 1.310 SECONDS 2.9 Mb LNX200-121 Random Shortest Path Example: Multiple Instances 10/04/01 13:16:13 PAGE 3 GAMS Rev 121 Linux/Intel L O O P S iter iter1 S O L V E S U M M A R Y MODEL short OBJECTIVE shortestPathLength TYPE LP DIRECTION MINIMIZE SOLVER CPLEX FROM LINE 43 **** SOLVER STATUS 1 NORMAL COMPLETION **** MODEL STATUS 1 OPTIMAL **** OBJECTIVE VALUE 11.1691 RESOURCE USAGE, LIMIT 0.300 1000.000 ITERATION COUNT, LIMIT 39 10000 GAMS/Cplex Mar 21, 2001 LNX.CP.CL 20.0 019.019.039.LNX For Cplex 7.0 Using environment variable ILOG_LICENSE_FILE to look for a Cplex license. Cplex 7.0.0, GAMS Link 19 Optimal solution found. Objective : 11.169132 **** REPORT SUMMARY : 0 NONOPT 0 INFEASIBLE 0 UNBOUNDED Random Shortest Path Example: Multiple Instances 10/04/01 13:16:13 PAGE 4 Model Statistics SOLVE short USING LP FROM LINE 43 GAMS Rev 121 Linux/Intel LOOPS iter iter2 (lots of junk deleted) L O O P S iter iter100 S O L V E S U M M A R Y MODEL short OBJECTIVE shortestPathLength TYPE LP DIRECTION MINIMIZE SOLVER CPLEX FROM LINE 43 **** SOLVER STATUS 1 NORMAL COMPLETION **** MODEL STATUS 1 OPTIMAL **** OBJECTIVE VALUE 7.8200 RESOURCE USAGE, LIMIT 0.270 1000.000 ITERATION COUNT, LIMIT 22 10000 GAMS/Cplex Mar 21, 2001 LNX.CP.CL 20.0 019.019.039.LNX For Cplex 7.0 Using environment variable ILOG_LICENSE_FILE to look for a Cplex license. Cplex 7.0.0, GAMS Link 19 Optimal solution found. Objective : 7.819959 **** REPORT SUMMARY : 0 NONOPT 0 INFEASIBLE 0 UNBOUNDED Random Shortest Path Example: Multiple Instances 10/04/01 13:16:13 PAGE 202 E x e c u t i o n GAMS Rev 121 Linux/Intel ---- 54 Arc Density ---- 54 PARAMETER density = 0.010 ---- 55 Proportion of Successful Paths: ---- 55 PARAMETER proportionOfSuccess = 1.000 ---- 56 Average length of Successful Paths: ---- 56 PARAMETER averageLength = 12.13437347 EXECUTION TIME = 0.080 SECONDS 52.2 Mb LNX200-121 USER: Computer Sciences Dept. G010628:1627AS-LNX University of Wisconsin-Madison DC2621 **** FILE SUMMARY INPUT /afs/cs.wisc.edu/u/s/w/swright/public/html/635/examples/short2.gms OUTPUT /afs/cs.wisc.edu/u/s/w/swright/public/html/635/examples/short2.lst